add cache clean before test run

Author: rostikts

Makefile

@@ -17,7 +17,7 @@ deploy: build
 	scp -qr ./sql/* sb-poc:/home/dstpierre/sql/
 
 alltest:
-	@go test --race --cover ./...
+	@go clean -testcache && go test --race --cover ./...
 
 thistest:
 	go test -run $(TESTNAME) --cover ./...